Dwayne F. Jackson, contract welder, age 34, was fatally injured on April 25, 2001, when he was engulfed by material. The victim was in a material storage bin when material was being discharged from the bin.

The accident occurred because there was a lack of effective communication between the victim and the employee that drew the material through the discharge chute. Contributing to the severity of the accident was failure to wear a safety belt and line with a second person tending the line.

Jackson had a total of eight months mining experience, all with the same contractor, as a welder, at this mine. He had received training in accordance with 30 CFR Part 46.

GENERAL INFORMATION

Columbus Quarry and Plant, a crushed granite operation, owned and operated by Florida Rock Industries, Inc. was located at 3001 Smith Road, Columbus, Muscogee County, Georgia. The principal operating official was Thomas Rector, area manager. The plant was normally operated one, 10-hour shift a day, five days a week. Total employment was 16 persons.

Granite was drilled and blasted then loaded into trucks and hauled to the plant where it was crushed, washed, screened, sized and stockpiled. The finished product was transported by conveyor to a rail and truck loadout facility that consisted of five 150-ton bins where it was loaded into customer trucks or railroad cars. The final product was sold for use as a construction aggregate.

The victim was employed by GW Systems, located in Birmingham, Jefferson County, Alabama. GW Systems was contracted to construct the plant which included the bins and to make alterations to ensure the material would flow through the bins without hangups. The principal operating official was Francis Glenn, president. Five contract employees were working at the mine when the accident occurred. They worked an average of 10 hours a day, 5 days a week at this mine.

Columbia Quarry and Plant was a new operation. A regular inspection had not been completed prior to the accident. A regular inspection was conducted following the investigation.

DESCRIPTION OF ACCIDENT

On the day of the accident, Dwayne Jackson (victim), reported for work at 7:00 a.m., his regular starting time. He and John Stoker, field superintendent for the contractor, were assigned to weld angle iron and deflectors in the number three loadout bin to make the bin self-cleaning.

At about 9:00 a.m., after the bin discharge controls had been locked out, they entered the bin and began welding. At this time the bin was partially filled with material to provide a work platform for them to stand on. Jackson had welded several pieces of metal in the bin and at about 2:30 p.m., they left the bin because additional material needed to be drawn from the bin so they could continue welding.

Stoker operated the manual discharge valve on the rail loadout chute at the bottom of the bin while Jackson was to remain on the walkway at the top of the bin to advise Stoker when enough material had been withdrawn. The material Stoker drew through the chute was dumped onto a conveyor belt and then onto the ground. The company loader operator used the front-end loader to scoop the material up and piled it to the side. After drawing off about two bucket loads of material, Stoker stopped the belt to see if enough material had been withdrawn. He proceeded to the south side of the bins and met Jackson on the steps. Jackson told Stoker that the material would need to be lowered a little more.

Stoker went back to the chute valve and began drawing down more material. After several minutes, Stoker saw Jackson's feet and legs in the chute. He went to the top of the bin to look for Jackson and found that he was completely engulfed by the material. Stoker ran to his truck and called for assistance on the CB radio. A 911 call was made to the local emergency medical services.

Additional rock was drawn down through the truck loadout chute. When enough material had been removed, EMT personnel entered the bin and performed resuscitation procedures on Jackson. He was removed from the bin and transported to a local hospital where he was pronounced dead due to compression asphyxia.

INVESTIGATION OF THE ACCIDENT

MSHA was notified of the accident at 4:35 p.m. on the day of the accident by a telephone call from Ronald Milligan, safety and training coordinator for Florida Rock Industries, Inc., to Donald L. Collier, mine safety and health inspector. An investigation was started that day. An order was issued under the provisions of Section 103(k) of the Act to ensure the safety of miners. MSHA's accident investigators traveled to the mine, made a physical inspection of the accident scene, interviewed employees, and reviewed conditions and work procedures at the time of the accident. MSHA conducted the investigation with the assistance of both mine and contractor management and employees. The miners did not request nor have representation during the investigation.

DISCUSSION

� The accident occurred in the number 3 bin of a five bin, gravity-feed, loadout facility. The bins were in line and adjacent to one another. Each bin had a 150-ton capacity, was 25-feet 6-inches deep, and had a 16-foot by 16-foot square opening at the top. The lower half of each bin was shaped like an inverted pyramid, with a center discharge chute (for loading trucks) at the bottom, and a side discharge chute (for loading rail cars) on the north wall of the pyramidal portion of the bin. The side discharge chute emptied onto a 42-inch conveyor that carried the crushed stone to the eastern side of the facility, where railroad tracks were to be located. The tops of the bins were approximately 46 feet above ground level.

� Crushed stone was carried into the bins on a 42-inch conveyor that spanned from ground level to the top of the facility, where it discharged onto a 48-inch shuttle conveyor. The shuttle conveyor was track mounted and could be positioned back and forth on tracks to discharge the crushed stone into the selected bin.

� Flow from the bins was controlled by opening and closing a clamshell type door at the bottom of each discharge chute. The discharge chute openings were square and measured 1 foot, 4 inches by 1 foot, 4 inches. The system was operated pneumatically. A double acting air cylinder at each discharge chute provided the force to open and close the two halves of the clamshell door. When the cylinder extended, the door closed and when the cylinder contracted the door opened. The two halves of each door were mechanically interlocked such that both opened and closed symmetrically. The air cylinders were made by the Sheffer Corporation, and had cylinder tubes that were 13" long and had an outside diameter of 3".

Each discharge chute door was controlled by a two-position, single-solenoid, spring-return, 120 Volt AC, pneumatic valve (Mac Valves, Inc., Model No. 82A-AA-CAA-TM-DAAP-1DA). When voltage was applied to the valve, air pressure was sent to the rod end of the cylinder and the door fully opened. When the voltage signal was cut off, air pressure was sent to the blind end of the cylinder and the door closed completely.

Each discharge chute door could also be opened by manually pushing a spring return button on the corresponding Mac control valve body. As long as the button was held down, the rod end of the cylinder was pressurized and the door remained open. Upon release, the blind end of the cylinder was pressurized and the door closed. The two Mac control valves for each bin could be manually operated while standing on a walkway near the side discharge chute.

� A manual shut-off valve was installed at the inlet of each Mac control valve that could isolate it from supply air. When no air pressure was supplied to the cylinder, the door would swing partially shut due to gravity.

� The load out facility was designed to allow remote operation of the center discharge and side discharge chute doors from a nearby building. However, the facility was still under construction at the time of the accident and the electric circuit to allow remote operation of the side discharge chute doors was not yet completed. The center discharge chutes could be operated remotely, but not the side chutes.

� No defects were found in the operation of the discharge chute doors of bin number 3 when the Mac control valve was operated manually. (It was reported that at the time of the accident, the Mac control valve was being operated manually to discharge crushed granite from the side chute of bin # 3.)

� No defects were found in the remote operation of the center chute door of bin # 3.

� A 26-inch wide walkway surrounded the top of the bins where the victim was reportedly located prior to the accident. Railing and toeboards were provided on both sides of the walkway and the floor was made of expanded metal decking. The top rail was 42 inches above the walkway and the intermediate rail was 21� inches above the walkway. The toeboard was 5 inches high. The railing and toeboards covered the complete perimeter of the walkway with no damaged or missing sections.

� The amount of aggregate material left in the bin when the victim's boots emerged from the discharge chute was estimated to be 1,300 cubic feet (approximately 62.5 tons, based on a density of 96 lbs per cu ft for crushed granite). This was based on measurements of the pile of aggregate that was released during the rescue attempt and the amount of aggregate estimated to be remaining in the bin. This would place the aggregate level, if evenly spread out, at approximately 12� feet above the bottom of the bin and 13 feet below the top. The aggregate level when the victim entered the bin would have been somewhat higher, but the exact level could not be determined since it was not known how long the victim was in the bin as it was being emptied.

� The two workers were in the process of installing angle irons on the inside vertical corners of the bin at the time of the accident. A total of 10 pieces was to be installed. Eight pieces had been welded in place. The two remaining sections were the bottom sections of the northeast and southeast corners. These last two sections were to be installed such that the bottom end of the angle irons would have been located approximately 14� feet below the top of the bin.

� The examination and testing of the manual controls for the discharge chute doors of bin number 3 did not reveal the existence of any defects.

CONCLUSION

The primary cause of the accident was material being drawn from the bin while the victim was inside. Contributing to the severity of the accident was failure to wear a safety belt and line with a second person tending the line. Failure of effective communication between the victim and the employee lowering the material through the discharge chute was also a contributing cause.

VIOLATIONS

Order No. 6076029 was issued on April 25, 2001, under the provisions of Section 103(k) of the Mine Act:

A contractor employee was fatally injured at this operation on April 25, 2001 when he was engulfed by material inside a loadout storage bin. The victim was inside the bin to perform welding tasks at the time of the accident. This order is issued to assure the safety of personnel at this operation until the mine or affected areas can be returned to normal mining operations as determined by an authorized representative of the Secretary. The mine operator shall obtain approval from an authorized representative for all actions to recover persons, equipment and/or restore operations in the affected area.

This order was terminated on May 2, 2001. Conditions that contributed to the accident have been corrected and normal mining operations can resume.

Citation No. 6089925 was issued on May 14, 2001, under the provisions of 104(a) of the Mine Act for violation of 30 CFR 56.16002(c):

A fatal accident occurred at this operation on April 25, 2001, when a contract welder was engulfed by crushed stone. The welder was in the bin when material was being discharged from the bin. The victim was not wearing a safety belt or harness equipped with a lifeline suitably fastened. A second person, similarly equipped, was not stationed nearby to attend the lifeline.

This citation was terminated on May 22, 2001. All contractor employees have received additional training in the requirements of 30 CFR 56.16002(c).

Citation No. 6089926 was issued on May 14, 2001, under the provisions of 104(a) of the Mine Act for violation of 30 CFR 56.9310(a):

A fatal accident occurred at this operation on April 25, 2001, when a contract welder was engulfed by crushed stone. The welder was in the bin when material was being discharged from the bin. Prior to the material in the bin being lowered, the victim was not properly warned or given time to clear the hazardous area.

This citation was terminated on May 22, 2001. All contractor employees have received additional training in the requirements of 30 CFR 56.9310(a).